Internet protocol trunk groups

ABSTRACT

A system includes a core routing engine operable to receive a call setup request and identify one or more IP trunk groups through which the call setup request can be routed, select one of the one or more identified IP trunk groups and route the call setup request to an internal IP address associated with the selected IP trunk group. The system may further include an IP edge node associated with the internal IP address, the IP edge node in the backbone network and operable to receive the call setup request and route the call setup request to one of a plurality of IP addresses associated with a plurality of carrier edge nodes in the carrier network.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation of U.S. patent applicationSer. No. 11/755,604, filed May 30, 2007, which claims the benefit ofpriority to Provisional Patent Application Ser. No. 60/823,935 entitled“Internet Protocol Trunk Groups”, filed Aug. 30, 2006, which isincorporated herein by reference for all purposes.

COPYRIGHT NOTICE

Contained herein is material that is subject to copyright protection.The copyright owner has no objection to the facsimile reproduction ofthe patent disclosure by any person as it appears in the Patent andTrademark Office patent files or records, but otherwise reserves allrights to the copyright whatsoever. Copyright © 2006 Level 3Communications, Inc.

TECHNICAL FIELD

Embodiments of the present invention generally relate to communicationsthrough a network. More specifically, embodiments relate to defininglogical groups of IP interconnections that have useful commonalities,and using the defined IP interconnection groups to route calls throughone network to another network.

BACKGROUND

In the field of network communications, Voice over Internet Protocol(VoIP) calls are typically setup over multiple networks, such as abackbone network and one or more customer or carrier networks.Typically, when a call request enters the backbone network, a corerouting device determines how to most efficiently route the call out ofthe backbone network to the customer network. The core routing devicechooses among a number of edge devices on the backbone network thatinterconnect with edge devices on the customer network. The choice ofwhich edge device to route to within the backbone network is typicallybased on the called telephone number and/or an associated IP address. Arouting tree of customer telephone numbers and customer IP addresses isaccessed to determine the outbound edge device. In conventional systems,one or more outbound edge devices on the backbone network are dedicatedto each customer network. For example, the routing trees, as well asother customer network-related data, are typically hard-coded in thebackbone edge devices. Such dedicated approaches have drawbacks relatedto lack of flexibility, lack of scalability, and heightened sensitivityto customer network changes.

When outbound devices are dedicated to a customer, devices that performcall routing functions in the interior of the backbone network oftenneed to be aware of (e.g., programmed with) details of theinterconnections to customer network. For example, a core routing enginemay need to have information about particular IP addresses that can bedirectly reached by the outbound edge devices. Such an arrangement tendsto make the core routing devices inefficient because these devices oftenneed to perform relatively complex processing to determine whichoutbound devices to use to route calls. In addition, the core routerconfiguration is highly sensitive to changes in IP addresses on thecustomer network. Conventionally, the outbound devices have not shieldedthe core routing equipment from changes, but rather, a change to thecustomer network often ripples through the backbone network, requiringchanges at multiple levels of the infrastructure.

Changes to network interconnections can also impact other aspects oftelecommunications service, such as billing and operations. For example,IP addresses on the customer network may be associated with bills thatare issued by the backbone network service provider to the customernetwork provider. When IP addresses change, if the billing system is notpromptly updated, then bills may be wrong; e.g., the bills may notcorrespond to the actual number of VoIP addresses being serviced. Thereoften is a separation between the update to the backbone networkinfrastructure and the other business processes, so that the change willneed to be made not only in the outbound edge devices, to maintainproper routing, but also in the billing systems, operations, and others.As such, customization to the customer network necessitates changes invarious aspects of the backbone network. However, conventionalapproaches toward responding to such customer changes have generally notbeen coordinated or efficient.

It is with respect to these and other considerations that embodiments ofthe present invention have been made.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary operating environment within whichembodiments of the invention can operate to define and use InternetProtocol (IP) trunk groups for routing calls from one network toanother.

FIG. 2 illustrates one general form of an IP trunk group configuration,in which the edge node of a VoIP backbone network is directly connectedto an interface node of a carrier network.

FIG. 3 illustrates another general form of an IP trunk groupconfiguration, in which a load-balancer can be accessed by an interfacenode of the carrier network to provide load balancing across multiplebackbone IP addresses included in an IP trunk group.

FIG. 4 illustrates yet another general form of an IP trunk groupconfiguration, in which a load-balancer is logically positioned betweenone or more edge nodes of the backbone network and one or more interfacenodes of the carrier network.

FIGS. 5 a-5 d illustrate various exemplary scenarios in which InternetProtocol (IP) trunk groups can be used.

FIG. 6 illustrates a data structure with attributes, values, andconstraints that can be used to define IP trunk groups in accordancewith one embodiment.

FIG. 7 illustrates a scheme that can be used by a core routing engine toroute incoming calls to outbound trunk groups.

FIG. 8 is a flowchart illustrating an exemplary process for defining andprovisioning IP trunk groups in a backbone network.

FIG. 9 is a flowchart illustrating an exemplary process carried out by acore routing engine for routing inbound calls to outbound IP trunkgroups in accordance with one embodiment.

FIG. 10 illustrates a general purpose computing device upon whichembodiments of the present invention can execute.

While the invention is amenable to various modifications and alternativeforms, specific embodiments have been shown by way of example in thedrawings and are described in detail below. The intention, however, isnot to limit the invention to the particular embodiments described.

DETAILED DESCRIPTION

Embodiments of the present invention relate to systems and methods fordefining trunk groups for use in an Internet protocol (IP) environment.More specifically, embodiments relate to identifying IP interconnectionsthat have common characteristics which can be included in an IP trunkgroup definition. IP trunk groups that are defined can be used by one ormore core routing engines to route incoming calls to outbound IP trunkgroups. Based on IP trunk group traffic distribution policies, inboundcalls are distributed across IP edge nodes, which may perform trafficdistribution across carrier network edge nodes.

Prior to describing one or more preferred embodiments of the presentinvention, definitions of some terms used throughout the description arepresented.

Definitions

The term “Internet protocol trunk group” or “IP trunk group” refers to agroup of one or more IP interconnections that have similar attributes.The one or more IP interconnections can be identified by an IP trunkgroup (IPTG) identifier.

The term “IP interconnection” refers to a logical path between two IPaddresses over an IP network and endpoints at each end of the logicalpath. An IP interconnection may include numerous physical paths throughthe IP network (e.g., different paths for different packets).

A “module” is a self-contained functional component. A module may beimplemented in hardware, software, firmware, or any combination thereof.

The terms “connected” or “coupled” and related terms are used in anoperational sense and are not limited to a direct connection orcoupling.

The phrases “in one embodiment,” “according to one embodiment,” and thelike generally mean the particular feature, structure, or characteristicfollowing the phrase is included in at least one embodiment of thepresent invention, and may be included in more than one embodiment ofthe present invention. Importantly, such phases do not necessarily referto the same embodiment.

If the specification states a component or feature “may”, “can”,“could”, or “might” be included or have a characteristic, thatparticular component or feature is not required to be included or havethe characteristic.

The terms “responsive” and “in response to” includes completely orpartially responsive.

The term “computer-readable media” is media that is accessible by acomputer, and can include, without limitation, computer storage mediaand communications media. Computer storage media generally refers to anytype of computer-readable memory, such as, but not limited to, volatile,non-volatile, removable, or non-removable memory. Communication mediarefers to a modulated signal carrying computer-readable data, such as,without limitation, program modules, instructions, or data structures.

Exemplary System

FIG. 1 illustrates an exemplary operating environment 100, which issuitable for employing Internet protocol trunk groups (IPTG) inaccordance with one embodiment. IPTGs can introduce a level ofabstraction between the interior infrastructure of a backbone networkand customer networks, to which the backbone network routes calls. Inthis regard, the IPTGs can insulate interior infrastructure fromcustomer network changes. In addition, IPTGs bundle various types ofinformation about IP interconnections that can be used by varioussystems associated with the backbone network. As such, IPTGs can allowfor scalability across the systems. Embodiments described herein aredirected at Voice over IP (VoIP), Session Initiation Protocol (SIP), andrelated technologies for purposes of illustration, although it will beunderstood by those skilled in the art that IPTGs and related conceptscan be applied to other communication environments and protocols.

In the embodiment of FIG. 1, a backbone network 102 providescommunications services between users who may access the same ordifferent communication networks, such as a switched network 104 and acarrier IP network 106. The switched network 104 could include thePublic Switched Telephone Network (PSTN), a local exchange carrier (LEC)network, cellular networks, and/or an emergency services network. Thecarrier IP network 106 could include an Internet Service Provider (ISP)network, an autonomous system, or other customer carrier network. Aplurality of communication endpoints 108 are used to access the switchednetwork 104, while a plurality of IP communication endpoints 110 areused to access the carrier IP network 106. Communication endpoints 108could include, without limitation, conventional telephones, cellulartelephones, facsimile machines (Fax), MODEMs, or telephones on a privatebranch exchange (PBX). IP communication endpoints 110 could include,without limitation, VoIP phones, soft phones, conference servers, IPinteractive voice response (IVR) platforms, or terminal adapters.

Calls routed by the backbone network 102 to the carrier IP network 106are routed through a publicly accessible IP network, such as theInternet 112. Communications through the Internet 112 can be public orprivate. For example, Communications may by privately communicated overthe Internet via an IP virtual private network (VPN). It will beunderstood that one or more of the switched network 104, the backbonenetwork 102, the Internet 112, and the carrier IP networks 106 could becomposed of multiple sub-networks.

In one scenario, calls are communicated between the switched network 104and the backbone network 102 in one format and/or protocol, while callsare communicated between the backbone network 104 and the carriernetworks 106 in another format and/or protocol. As such, among otherfunctions, the backbone network 102 performs translation of the callsbetween the protocol of the switched network 104 and the InternetProtocol of the carrier networks 106. In other scenarios, calls can becommunicated between IP communication endpoints 110 on one or moreIP-based carrier networks 106.

In the embodiment of FIG. 1, calls between the switched network 104 andthe backbone network 102 are communicated using Time-divisionMultiplexing (TDM). More specifically, multiple TDM trunk groupsfacilitate the interface between the backbone network 102 and theswitched network 104.

Multiple IP interconnections exist between the backbone network 102 andthe carrier IP networks 106 to facilitate call communication betweenthese networks over the Internet 112. As is known, communications overthe Internet are packetized, and packets of a single communication couldtake multiple different paths through the Internet. When the packetsreach their destination, they are reassembled. An IP interconnectionincludes two end nodes and the logical path formed between them by theone or more paths through the Internet that packets of a communicationtake. Multiple IP trunk groups 116 may be defined over sets of the IPinterconnections, as is described in further detail below. Using theIPTGs 116, interior systems of the backbone network 102 can efficientlyroute calls from the switched network 104 and the carrier IP networks106 and vice versa. The backbone network 102 can also route calls fromone IP-based network 106 to another IP-based network 106.

More specifically, core routing engines (CREs) 118 in the backbonenetwork 102 route calls from TDM edge nodes 120 to IP edge nodes 122 orfrom IP edge nodes 122 to other IP edge nodes 122. IP edge nodes 122route the received calls to carrier edge nodes 124. The TDM edge nodes120 and the IP edge nodes are typically gateway devices. In variousembodiments, media gateways on the edge of the backbone network 102 arecontrolled by media gateway controllers. The media gateways and themedia gateway controllers may or may not be separate devices. IP mediagateways may be referred to as session border controllers (SBCs). Mediagateways (MGs), MG controllers and other associated components areavailable and are manufactured and distributed by various equipmentproviders such as Sonus™ and Lucent™, just to name a few. The presentinvention is certainly not limited to any certain brand name, but rathervarious embodiments may be implemented using any one or more of theseknown providers.

When a CRE 118 receives call requests (e.g., SIP requests or INVITEs)from a TDM edge node 120, in general, the CRE 118 chooses among multipleIP edge nodes 122 through which to route the call requests. Thedetermination as to which of multiple IP edge nodes 122 to choose isfundamentally based on the called telephone number in the request. Thecalled telephone number dictates the IP address of the destination onthe carrier IP network 106. However, choosing the IP edge node 122 canbe based on routing policies. These routing policies are generallyconfigurable based on various criteria such as, but not limited to,device capabilities, load balancing, or device or system settings orconnections. Exemplary routing policies are discussed further below,with reference to IP trunk groups, which facilitate implementation ofthe routing policies.

FIGS. 2-4 illustrate three basic types of IP interconnections that canform IP trunk groups. The IP interconnections are logical IPinterconnections rather than physical. It is to be understood that theseare not the only types of IP trunk groups. The exemplary typesillustrated in FIGS. 2-4 have been developed with regard to variationsin carrier IP network interconnection profiles and equipmentcapabilities. Selection of a type of IPTG can depend on numerousconsiderations such as, but not limited to, the ability and willingnessof the carrier to support call distribution and load balancing acrossthe backbone IP interconnection edge topology, the ability andwillingness of the carrier to use congestion control mechanisms for bothinbound and outbound flows, and the ability and willingness of thecarrier to normalize SIP signaling in accordance with SIP interfacespecifications of the backbone network and follow standardized SIPbehaviors. While the foregoing are not the only considerations indetermining the optimal IPTG interconnection type, they account for someimportant factors.

FIG. 2 illustrates one possible type of IP interconnection 200 that canform a component of an IP trunk group (IPTG). In this embodiment, thebackbone network 102 IP edge node 122 is logically connected to thecarrier edge node 124 of the carrier network 106. The type of IPinterconnection illustrated in FIG. 2 is referred to as an IP directinterconnection 200. IP direct interconnections 200 are “direct” SIP/IPconnections between the backbone network IP edge nodes 122 and thecarrier edge nodes 124. The term “direct” is used here merely todistinguish this type of interconnection from other types ofinterconnections described below that include Load Balancers (LBs).Although the IP interconnection 200 does not utilize LBs, it will beunderstood that between the IP edge node 122 and the carrier edge node124 there may be routers and other devices that facilitate communicationbetween the nodes.

An IPTG formed from the IP interconnection type of FIG. 2 can becharacterized by a number of elements. The logical path 202 of theinterconnection 200 corresponds to the IPTG identification. As discussedfurther below, the logical path 202 is given a name or other identifierwith which the IPTG can be associated and referenced. An internal IPaddress 204 is a SIP signaling IP address of the IP edge node 122 thatcontrols the IPTG. The internal IP address 204 is private and internalto the backbone network 102. The IPTG is further characterized by thename or other identifier of the IP edge node 122 that controls the IPTG.A public external IP Address 206 of the IP edge node 122 is a SIPsignaling IP address that is accessible to one or more carrier edgenodes 124. A public external IP address of the carrier edge node 124 isa SIP signaling IP address involved with the IPTG. The IPTG is furthercharacterized by the name or other identifier of the carrier edge node124.

In embodiments that use IP direct interconnections 200, the backbonenetwork 102 IP edge node 122 manages the IPTG on both an inbound (i.e.,into the backbone network 102 from the carrier IP network 106) andoutbound (from the backbone network 102 to the carrier IP network 106)basis. For example, the IP edge nodes 122 determine the appropriate IPoriginating trunk group (OTG) for the call and pass an OTG identifier tothe CRE. With regard to outbound calls, the IP edge nodes 122 translatethe provided destination trunk group (DTG) into a specific carrier IPAddress (or set of IP addresses).

In addition, for embodiments that use direct IP interconnections 200 thecarrier edge node 124 manages load balancing between multiple backbonenetwork 102 IP edge nodes 122 for inbound calls. Likewise, outbound callload balancing between carrier edge nodes 124 is handled by the IP edgenodes 122 at the IP address layer, and the CRE at the IPTG layer. Stateddifferently, the backbone network 102 CRE 118 balances load betweenIPTGs while the backbone network 102 IP edge nodes 122 balance loadbetween IP addresses, if there is more than one carrier IP address inthe IPTG.

FIG. 3 illustrates another type of IP interconnection 300. This type ofIP interconnection 300 uses a SIP re-direct load balancer for inboundcalls (i.e., from the carrier network 106 to the backbone network 102),and follows the same convention as the IP direct interconnection type(e.g., 200, FIG. 2) for outbound calls (i.e., from the backbone network102 to the carrier network 106). The type of IP interconnection shown inFIG. 3 is referred to as an inbound load-balanced IP interconnection.

An IPTG that includes an inbound load-balanced IP interconnection can becharacterized by a number of elements. The logical path 302 between thecarrier edge node 124 and the IP edge node 122 corresponds to the IPTGIdentification. As discussed further below, the logical path 302 isgiven a name or other identifier with which the IPTG can be associatedand referenced. An internal IP address 304 is a SIP signaling IP addressof the IP edge node 122 that controls the IPTG. The internal IP address304 is private and internal to the backbone network 102. The IPTG isfurther characterized by the name or other identifier of the IP edgenode 122 that controls the IPTG. A public external IP Address 306 of theIP edge node 122 is a SIP signaling IP address that is accessible to oneor more carrier edge nodes 124. A public external IP address 308 of thecarrier edge node 124 is a SIP signaling IP address involved with theIPTG. The IPTG is further characterized by the name or other identifierof the carrier edge node 124.

In an inbound load-balanced IP interconnection a SIP re-direct loadbalancer 310 is employed so that inbound SIP signaling from the carrieredge nodes 124 is balanced across multiple IP edge nodes 122. The IPTGincluding an inbound load-balanced IP interconnection is furthercharacterized by an IP Address 312 of the SIP re-direct load balancer310. Inbound load-balanced IP interconnection 300 types are similar todirect IP Interconnections in the sense that in both types the backbonenetwork 102 IP edge nodes 122 manage the IPTG on both an inbound andoutbound basis. However, the SIP re-direct load balancer 310 provides alayer of abstraction between the carrier edge nodes 124 and the backbonenetwork 102 edge node 122 topology.

In the inbound load-balanced IP interconnection 300, inbound carriercalls are sent to the SIP re-direct load balancer 310. The LB 310responds with a 300 MC SIP message containing one or more backbonenetwork 102 IP edge node 122 external IP addresses. The IP edge nodes122 determine the appropriate origination trunk group (OTG) and pass theOTG's identifier to the CRE 118. As with direct IP Interconnection type,for outbound calls the IP edge nodes 122 translate the provided DTG intoa specific carrier edge node IP Address (or set of IP addresses).Outbound call load balancing between the carrier edge nodes 124 ishandled by the IP edge nodes 122 at the IP layer, and the CRE 118 at theIPTG layer.

In some embodiments that are not shown, an outbound SIP re-direct loadbalancer can be employed at the backbone network 102. In thisembodiment, the IP edge nodes 122 send calls to the outboundload-balancer (not shown) and the outbound load-balancer responds withone or more external IP addresses of the carrier network edge nodes 124.This type of IP interconnection is referred to as an outboundload-balanced IP interconnection.

In yet another embodiment, both an outbound SIP re-direct load balanceris employed at the backbone network 102 and an inbound SIP re-directload balancer is employed at the carrier network 106. This type of IPinterconnection is referred to as a hybrid load-balanced IPinterconnection.

FIG. 4 illustrates yet another type of IP interconnection 400 that canbe used in IPTGs. The IP interconnection 400 shown in FIG. 4 is referredto as a SIP proxy load balanced IP interconnection because a SIP proxyload balancer 402 is logically positioned between the IP edge nodes 122of the backbone network 102 and the carrier edge nodes 124 of thecarrier network 106. The SIP proxy load balancer is used for bothinbound and outbound calls.

An IPTG that includes a SIP proxy load-balanced IP interconnection 400can be characterized by a number of elements. The logical path 404between the carrier edge node 124 and the SIP proxy load-balancer 402corresponds to the IPTG identification. The logical path 404 is given aname or other identifier with which the IPTG can be associated andreferenced. An internal IP address 406 is a SIP signaling IP address ofthe IP edge node 122 that controls the IPTG. The internal IP address 406is private and internal to the backbone network 102.

The IPTG is further characterized by the name or other identifier of theIP edge node 122 that controls the IPTG. A public external IP Address408 of the IP edge node 122 is a SIP signaling IP address that isincluded in the IPTG. A public external IP address 410 of the carrieredge node 124 is a SIP signaling IP address involved with the IPTG. TheIPTG is further characterized by the name or other identifier of thecarrier edge node 124 involved with the IPTG.

The SIP proxy load balancer 402 used by the carrier edge nodes 124 isfor inbound SIP signaling and the backbone IP edge nodes 122 foroutbound SIP signaling. In the embodiment of FIG. 4, the backbone IPedge nodes 122 only partially manage the IPTG. As with the inbound SIPre-direct load balanced type of IP interconnection 300 shown in FIG. 3,the SIP proxy load balanced interconnection 400 provides a layer ofabstraction between the carrier edge node and the backbone IP edge node122 topology. In addition, the SIP proxy load balanced IPinterconnection also abstracts the carrier edge node 124 topology and IPaddressing from the backbone IP edge nodes 122. Because of thisbi-directional abstraction, the management of IPTGs is distributedbetween the edge nodes 122, 124 and the load balancers 400.

Inbound calls arriving from carrier networks in a SIP proxy loadbalanced IP interconnection will be directed to a public IP address onthe LB 402. The SIP Proxy LB 402 determines the correct IP OTG for thecall and chooses the appropriate backbone IP edge node 122 to be usedfor the call. This selection can be based on varying algorithms toachieve load balancing, geographic POI optimization, etc.

When an inbound call arrives at the backbone IP edge node 122, the callwill already contain an IP OTG designation that was determined from theSIP Proxy LB 402. Thus, the backbone IP edge node is not responsible fordetermining the IP OTG and passes the IP OTG information on to the CRE118.

With regard to outbound calls from the backbone network 102 on a SIPproxy load balanced IP interconnection 400, the backbone IP edge nodesreceive a specified IP DTG to be used for call termination. This IP DTGis resolved into the appropriate SIP Proxy LB 402 IP Address 412, ratherthan the carrier edge node IP address 410. As such, the backbone IP edgenode is responsible for passing the call to the correct SIP Proxy LB 402while maintaining the specified IP DTG in the call's signaling.Subsequently, the SIP Proxy LB 402 resolves the IP DTG into one or morecarrier edge node IP addresses and forwards the call appropriately.

FIGS. 5 a-5 d illustrate a number of different IP trunk group usescenarios and arrangements. In general, an IP trunk group is defined byone IP address on the edge node of a first network, and one or more IPaddresses on one or more edge nodes of a second network.

In FIG. 5 a, multiple IP interconnections 502 a-502 n exist between anedge node 504 and multiple carrier interface nodes 506 a-506 n. The edgenode 504 has an external IP address 508. Each of the carrier interfacenodes 506 a-506 n have a corresponding external IP address 510 a-510 n,respectively. In one scenario, a first IP trunk group 512 logicallyincludes interconnections 502 a-502 n. In another scenario, a second IPtrunk group 514 and a third IP trunk group 516 are defined. The secondIP trunk group 514 logically includes IP interconnection 502 a, whilethe third IP trunk group 516 logically includes IP interconnections 502b-502 n.

In FIG. 5 b, a first IP interconnection 518 a exists between a first IPaddress 520 a of a first edge node 522 and a first IP address 524 a of acarrier interface node 526. A second IP interconnection 518 b existsbetween a second IP address 520 b of the first edge node 522 and asecond IP address 524 b of the carrier interface node 526. In thisscenario, two IP trunk groups are defined. A first IP trunk group 528logically includes the IP interconnection 518 a, and a second IP trunkgroup 530 logically includes the IP interconnection 518 b.

In FIG. 5 c, a first IP interconnection 532 a exists between an IPaddress 534 of an edge node 536 and a first IP address 538 a of acarrier interface node 540. A second IP interconnection 532 b existsbetween the IP address 534 of the edge node 536 and a second IP address538 b of the carrier interface node 540. Three possible IP trunk groupscan be defined given this arrangement. A first IPTG 542 includes both IPinterconnection 532 a and IP interconnection 532 b. A second IPTGincludes only IP interconnection 532 a, while a third IPTG includes onlyIP interconnection 532 b.

In FIG. 5 d, multiple IP interconnections 544 a-544 n exist betweenassociated backbone IP edge nodes 546 a-546 n and a single carrier edgenode 548. In this arrangement, each IP interconnection 544 can bedefined as an IPTG, but more than one of the IP interconnections 544 arenot grouped together.

FIG. 6 illustrates an exemplary data structure 600 in the form of a datatable, which can be used to store definitions of IP trunk groups. Inthis embodiment, regardless of the IP interconnection type used, thereis a fundamental set of parameters that describe an IPTG for thepurposes of call processing, reporting, mediation/billing, andprovisioning. A standardized database of records may or may not be usedto maintain these IPTG attributes so they can be used by otherprovisioning, reporting, routing, and configuration systems.

In the table 600, there is a set of attribute names 602, a set ofattribute values 604 and a set of constraints 606. With regard toconstraints 606, “S” means a Single Value is allowed per IPTG, “M” meansthat multiple values are allowed per IPTG, U means that a globallyunique value is used per IPTG, and “N” means that a non-unique value canappear in multiple IPTGs.

Referring now to the attribute names 602, every trunk group has a trunkgroup ID (TGID) 608. In the illustrated embodiment, the IPTG TGID fieldis a numeric value that serves as the overall name or reference for theIPTG. In one embodiment, the TGID is a globally unique value that isgenerated by an IPTG database when the associated IPTG is created.

An internal IP data field 610 contains a single standard IP address,signaling port, and transport type that denotes where the backbonenetwork internal signaling should be sent to reach a specified IP DTG.Each IPTG typically has a single Internal IP Address assigned to it, asIPTGs do not span multiple stateful edge devices. The internal IP dataattribute 610 is used by the CRE in conjunction with the TGID to denotea route choice in the backbone network. The three informational elementsof this field can be separated into individual related fields.

A facility name attribute 612 denotes the name of the facility in thebackbone network that corresponds to the internal IP address for theTGID. Each IPTG will typically have a single internal IP addressassigned to it, as IPTGs do not span multiple stateful edge devices. Invarious embodiments, the facility name attribute is sized to accommodatea single 30 character alphanumeric value.

An external IP data attribute 614 contains a single IP address,signaling port, and transport type that denotes the backbone IP edgenode of the IPTG. The external IP data attribute 614 specifies thepublic-facing IP address on the backbone network IP edge node for thisassociated TGID. In this embodiment, each TGID will contain a singlevalue for the backbone network external IP address. In SIP proxyload-balanced IP interconnections, the external IP data attribute willnot be used because the IPTG is not anchored to the backbone network IPedge node on the carrier network facing side. The three informationalelements of this field can be separated into individual related fieldsif desired.

A carrier IP data attribute 616 designates IP addressing information forthe carrier edge nodes involved with the IPTG. In one embodiment, the IPdata value denotes the IP Address(es), signaling port(s), and transporttype(s) associated with the TGID. The carrier IP data value may containmultiple sets of IP information per a single TGID. In one embodiment,the carrier IP data is sized to initially accommodate ten sets of IPinformation and is able to be increased in the future if needed. Theinformation in the carrier IP data field 616 may be separated intomultiple related fields if desired.

A carrier facility name attribute 618 designates the facility name ofthe carrier IP address(es) involved with the IPTG. In this embodiment,there is an associated facility name provided for every IP Address inthe carrier IP data attribute 616. In one embodiment, the carrierfacility name value is sized to initially accommodate ten facilitynames, with each facility name up to 20 alphanumeric characters, and thevalue may be able to be increased in terms of additional facility namesin the future if needed.

A size attribute 620 designates the size of the IPTG. In thisembodiment, the size value contains a single three digit value thatrepresents the TG's equivalent size in T1s. The size attribute is usedby the CRE when performing proportional routing allocation between TGs.In various embodiments, business and process rules are built around howthe size value is determined. This may involve applying systemsafeguards and/or constraints.

A pseudo carrier code (PCC)/customer profile value (CPV) attribute 622is used by the CRE to apply customized routing on an OTG basis. In oneembodiment, the PCC/CPV value contains a single five digit value thatrepresents the TGID's PCC.

An E911 type attribute 624 is used for proper routing of E911 calls forthe IPTG by the CRE. In this embodiment, the E911 value contains one ofthree possible values that represent the TGID's E911 service type:

-   -   N/A: this TGID does not require or is not allowed to use E911        service    -   12: this TGID requires E911 i2 type routing    -   TRADITIONAL: this TGID requires traditional CPN type E911        routing

A route advance profile attribute 626 specifies a route advance profilerelated to the IPTG. In one embodiment, the route advance profile valuecontains a single three digit value that denotes a specified routeadvance profile. The route advance parameters associated with eachprofile can be maintained in memory, and can be represented by analphanumeric identifier, such as a three digit value. In accordance withsome embodiments, the route advance profile attribute 626 is onlyapplicable for IPTGs that are Bi-directional or Inbound from adirectionality standpoint, and egress-only IPTGs will have a defaultvalue of 000 in this field.

A signaling normalization profile attribute 628 is used for signalingnormalization designation. In one embodiment the signaling normalizationprofile attribute 628 value contains a single three digit value thatdenotes a specified signaling normalization profile. These profiles canbe maintained in memory and can be represented by an alphanumericidentifier, such as a three digit value.

A directionality attribute 630 can be used to ensure that systems suchas route analysis tools are aware of IPTGs that are available for calltermination. In one embodiment, the directionality attribute 630contains one of three possible values that represent the IPTG'sdirectionality:

-   -   B (Bi-directional IPTG that supports both Ingress and Egress        use)    -   E (Egress-only IPTG supporting outbound use (DTG) only)    -   I (Ingress-only IPTG supporting inbound use (OTG) only)

A hunt sequence attribute 632 designates how an IP edge node shoulddistribute calls across an IPTG when multiple carrier IP addressesexist. In one embodiment, the value for the hunt sequence attribute 632can take on one of the following values:

-   -   P: calls will be sent to the IP addresses as a function of their        priority    -   LB: calls will be evenly distributed between all carrier IP        addresses

The hunt sequence value can be used by the backbone edge device thatmanages the IP DTGs to ensure calls are distributed to carriers in thedesired manner.

A regulatory nature attribute 634 indicates the regulatory nature ofcalls arriving on the IPTG. In one embodiment, the value of theregulatory nature attribute is selected from two possible values

-   -   E (all calls are considered to be Enhanced)    -   N (all calls are considered to be Non-Enhanced)

The regulatory nature attribute can be used by various backbone networkprovider systems to track the regulatory nature of the IPInterconnections.

A carrier ID attribute 636 denotes a carrier identifier for the carrierassociated with the IPTG. In one embodiment the carrier ID valuecontains a single 20 character alphanumeric value representing thecarrier's name as a function of other systems within the backbonenetwork provider.

An allowable codecs attribute 638 denotes values associated with codecsand packetization Intervals. In one embodiment, values for the allowablecodecs attribute contain up to ten values that denote the desired and/orsupported media codec and packetization intervals for the IPTG. Eachvalue may be in the format of codec:packetization (e.g. G.711:20 ms). Inone embodiment the allowable codecs value is sized to accommodate tenvalues, each no larger than 20 alphanumeric characters. The allowablecodecs attribute 638 can be used by the backbone network to establishthe supported and preferred media types for an IPTG.

A product ID attribute 640 denotes a product associated with the IPTG.In one embodiment, the product ID value contains a single 20 characteralphanumeric value related to a the backbone network provider productname.

An interconnection type attribute 642 denotes the type of IPinterconnection for the IPTG. Exemplary values for the interconnectiontype attribute are alphanumeric identifiers associated with the type.Exemplary types are described above, such as direct IP interconnection,SIP inbound re-direct load balanced IP interconnection, and SIP proxyload balanced IP interconnection.

A backbone network load balancer (LB) IP data attribute 644 is used forthe SIP load balanced IP interconnection types (e.g., inbound, outbound,hybrid, or proxy). The LB IP data attribute 644 denotes the LB IPaddresses, port, and transport mechanism that are associated with theTGID. In this embodiment the field for the value is sized to accommodatefour IP addresses.

A backbone network load balance type attribute 646 denotes the type ofbackbone network load balancing used for the IPTG. In accordance withone embodiment, the load balance type attribute 646 can take on thefollowing values: redirect—related to a SIP re-direct load balanced IPinterconnection; and proxy—related to a SIP proxy load-balanced IPInterconnection.

A carrier equipment data attribute 648 contains an alphanumeric valuerepresenting the carrier network's equipment (e.g., carrier edge node).In one embodiment, the carrier equipment data attribute value is asingle 30 character alphanumeric value. It will be understood that theattributes, fields, data, and formats illustrated in FIG. 6 anddescribed above are for illustration purposes only. The invention is notlimited to the illustrated and described implementation.

FIG. 7 illustrates an exemplary scheme that can be carried out by a corerouting engine of a backbone network for routing inbound calls tooutbound IP trunk groups in accordance with one embodiment. When a SIPrequest comes into the core routing engine, the core routing engineextracts the called telephone number 702. The core routing engine thenidentifies a corresponding route label from among multiple route labels704 a-704 n that are associated with telephone numbers.

Each route label 704 has an associated set of TGIDs 706. For example,route label 704 a has an associated set of TGIDs 706 a, route label 706b has an associated set of TGIDs 706 b, and so on. A TGID may or may notbe associated with more than one route label 704.

After the core routing engine determines the appropriate route label704, the core routing engine determines which TGID to which the callshould be sent. The core routing engine uses a TG traffic distributionpolicy 708 associated with the selected route label 704 to choose theTGID. In one embodiment, each TG traffic distribution policy 708specifies an order in which the TGIDs should be used. Some exemplarytraffic distribution policies are round robin, sequential, and percentallocation. Other traffic distribution policies can be used.

Exemplary Operations

FIGS. 8-9 illustrate processes that can be carried out to define one ormore IP trunk groups and use the defined trunk groups for routing callsthrough a backbone network. One or more of the operations shown in FIGS.8-9 can be embodied in a computer program product and executed by acomputing device, such as a core routing engine, an edge proxy server,or a session border controller. The particular order of the operationsshown is not absolute. Some of the operations can be rearranged, merged,and/or broken out into multiple operations, depending on the particularimplementation, without departing from the scope of the presentinvention.

In FIG. 8, a process 800 is illustrated for defining one or more IPTGs.In and identifying operation 802, one or more sets of IPinterconnections are identified, wherein each set can properly anddesirably be aggregated into associated IP trunk groups. Each set of IPinterconnections includes one or more IP interconnections. Generally, IPinterconnections that are grouped together are logically similar or havecommonalities that might offer economies of scale in grouping theinterconnections to together, but this is not necessary.

A determining operation 804 determines an IP interconnection type foreach of the sets of IP interconnections identified in operation 802.Some exemplary IP interconnection types are described above, but othersmay be developed and used in the determining operation 804. A definingoperation 806 defines an IP trunk group for each set of one or more IPinterconnections that were identified in operation 802. In oneembodiment, the defining operation 806 involves selecting values for aplurality of attributes such as those shown in FIG. 6. The definingoperation 806 also involves specifying one or more policies, such astraffic distribution policies (at the IPTG level and at the IP addresslevel), E911 routing policies, directionality policies, and so on.

A provisioning operation 808 provisions the IPTG definitions andpolicies to one or more backbone network IP edge nodes. Anotherprovisioning operation 810 provisions the IPTG definitions at one ormore backbone network core routing engines. Provisioning may involvestoring the definitions in a database accessible by the core routingengines and the edge nodes, or otherwise configuring the core routingengines and the edge nodes with the IPTG definitions. After the IPTGdefinitions are provisioned at the core routing engines and the edgenodes, they are used for routing calls through the backbone network.

FIG. 9 illustrates one possible algorithm 900 for routing calls througha backbone network using IPTGs. In a receiving operation 902, a corerouting engine receives a call request. The call may come in on a TDMtrunk through a PSTN gateway, which forwards the request to the corerouting engine. The core routing engine accesses a set of routing labelsto determine where and how to route the call. In a selecting operation904, the core routing engine selects an IP trunk group from a number ofdefined IPTGs. Selecting the IPTG is based at least in part upon thecalled telephone number and one or more policies associated with theIPTGs.

A forwarding operation 906 forwards the call request to the selectedIPTG. More specifically, the forwarding operation 906 sends the callrequest to an internal IP address associated with the selected IPTG. Arouting operation 908 is carried out by an edge node that received thecall request. In the routing operation 908, the edge node determineswhich IP address to route the call request to. The IP address may beassociated with a carrier edge node or a SIP proxy load balancer. An IPaddress of a carrier edge node may be obtained from a redirection devicesuch as a DNS server or a SIP redirector load balancer.

Exemplary Computing Device

FIG. 10 is a schematic diagram of a computing device 1000 upon whichembodiments of the present invention may be implemented and carried out.As discussed herein, embodiments of the present invention includevarious steps. A variety of these steps may be performed by hardwarecomponents or may be embodied in machine-executable instructions, whichmay be used to cause a general-purpose or special-purpose processorprogrammed with the instructions to perform the steps. Alternatively,the steps may be performed by a combination of hardware, software,and/or firmware.

According to the present example, the computing device 1000 includes abus 1001, at least one processor 1002, at least one communication port1003, a main memory 1004, a removable storage media 1005, a read onlymemory 1006, and a mass storage 1007. Processor(s) 1002 can be any knowprocessor, such as, but not limited to, an Intel® Itanium® or Itanium 2®processor(s), AMD® Opteron® or Athlon MP® processor(s), or Motorola®lines of processors. Communication port(s) 1003 can be any of an RS-232port for use with a modem based dialup connection, a 10/100 Ethernetport, a Gigabit port using copper or fiber, or a USB port. Communicationport(s) 1003 may be chosen depending on a network such a Local AreaNetwork (LAN), Wide Area Network (WAN), or any network to which thecomputing device 1000 connects. The computing device 1000 may be incommunication with peripheral devices (not shown) such as, but notlimited to, printers, speakers, cameras, microphones, or scanners.

Main memory 1004 can be Random Access Memory (RAM), or any other dynamicstorage device(s) commonly known in the art. Read only memory 1006 canbe any static storage device(s) such as Programmable Read Only Memory(PROM) chips for storing static information such as instructions forprocessor 1002. Mass storage 1007 can be used to store information andinstructions. For example, hard disks such as the Adaptec® family ofSCSI drives, an optical disc, an array of disks such as RAID, such asthe Adaptec family of RAID drives, or any other mass storage devices maybe used.

Bus 1001 communicatively couples processor(s) 1002 with the othermemory, storage and communication blocks. Bus 1001 can be a PCI/PCI-X,SCSI, or USB based system bus (or other) depending on the storagedevices used. Removable storage media 1005 can be any kind of externalhard-drives, floppy drives, IOMEGA® Zip Drives, Compact Disc-Read OnlyMemory (CD-ROM), Compact Disc-Re-Writable (CD-RW), Digital VideoDisk-Read Only Memory (DVD-ROM).

Based on the disclosure provided herein, one of ordinary skill in theart will appreciate a myriad of behaviors that may be quantified usingthe presented approach. Further, based on the disclosure providedherein, one of ordinary skill in the art will recognize a variety ofways that the aforementioned information may be used. For example, theaforementioned information may be used in a proactive way to modify thedesign of a particular transaction network to achieve betterperformance. Alternatively, the aforementioned information may be usedin a reactive way to cure identified failures in a network under test.Again, based on the disclosure provided herein, one of ordinary skill inthe art will appreciate a variety of ways that the information may beused.

Various modifications and additions can be made to the exemplaryembodiments discussed without departing from the scope of the presentinvention. For example, while the embodiments described above refer toparticular features, the scope of this invention also includesembodiments having different combinations of features and embodimentsthat do not include all of the described features. Accordingly, thescope of the present invention is intended to embrace all suchalternatives, modifications, and variations together with allequivalents thereof.

What is claimed is:
 1. A method for routing an Internet Protocol(IP)-based call through a first IP-based network to a second IP-basednetwork, the method comprising: receiving an IP-based call request inthe first network; identifying one or more IP trunk groups that can beused to route the call request out of the first network, wherein each ofthe one or more IP trunk groups represents a logical grouping of one ormore IP interconnections between the first IP-based network and thesecond IP-based network, wherein identifying one or more IP trunk groupscomprises accessing one or more IP trunk group definitions; mapping aroute label associated with a called telephone number to a set of theone or more IP trunk group definitions; selecting one of the one or moreIP trunk groups, wherein selecting one of the one or more IP trunkgroups comprises selecting the IP trunk group based on an IP trunk group(IPTG) traffic distribution policy specifying how to distribute callsamong IPTGs within a set of IPTGs; and routing the received call requestto an IP address associated with the selected IP trunk group.
 2. Themethod as recited in claim 1 wherein at least one of the one or more IPtrunk group definitions is associated with more than one route label. 3.The method as recited in claim 1 wherein each of the one or more IPtrunk group definitions includes one or more attributes selected from agroup consisting of: an IP trunk group identifier; an internal IPaddress associated with the first IP-based network; a facility nameassociated with the first IP-based network; an external IP addressassociated with the first IP-based network; an IP address associatedwith the second IP-based network; a facility name associated with thesecond IP-based network; a group size; a pseudo carrier code; anemergency services routing type; a group route advance profile; asignaling normalization profile; a directionality indicator; a huntsequence; regulatory nature data; a second IP-based network identifier;an allowable codecs indicator; a product identifier; an IPinterconnection type associated with the IP trunk group; a load balancerIP address; a load balancer type; and a second IP-based network edgenode type.
 4. The method as recited in claim 1 wherein the IPTG trafficdistribution policy is selected from a group consisting of: sequential;round-robin; and percentage allocation.
 5. A method for configuring aVoice over Internet Protocol (VoIP) backbone network to route calls toan IP-based carrier network, the method comprising: identifying one ormore sets of IP interconnections between the VoIP backbone network andthe IP-based carrier network that have common attributes; determining anIP interconnection type for each of the one or more identified sets ofIP interconnections; for each set of IP interconnections, defining anInternet Protocol (IP) trunk group wherein defining comprisesassociating the common attributes of each identified set of IPinterconnections with a unique IP trunk group identifier; accessing oneor more of the defined IP trunk group; and mapping a route labelassociated with a called telephone number to a set of the defined IPtrunk groups.
 6. A system for routing IP-based calls through a backbonenetwork to a carrier network, the system comprising: a core routingengine operable to receive a call setup request and identify one or moreIP trunk groups through which the call setup request can be routed,based at least in part on a telephone number in the call setup request,wherein identifying the one or more IP trunk groups comprises accessingone or more IP trunk group definitions, the core routing engine furtheroperable to map a route label associated with the telephone number to aset of the IP trunk group definitions and select one of the one or moreidentified IP trunk groups and route the call setup request to aninternal IP address associated with the selected IP trunk group; an IPedge node associated with the internal IP address, the IP edge node inthe backbone network and operable to receive the call setup request androute the call setup request to one of a plurality of IP addressesassociated with a plurality of carrier edge nodes in the carriernetwork; and a redirection device operable to receive the call setuprequest from the IP edge node and return one or more of the plurality ofIP addresses associated with the carrier edge nodes, whereby the IP edgenode can select from the one or more IP addresses to which to send thecall setup request.
 7. The system as recited in claim 6 furthercomprising a proxy load balancer operable to receive the call setuprequest from the IP edge node and direct the call setup request to oneof the plurality of IP addresses associated with the carrier edge nodes.8. The system as recited in claim 6 further comprising a redirectiondevice in communication with the plurality of carrier edge nodes andoperable to return one or more IP addresses of IP edge nodes on thebackbone network, in response to receiving a call setup request from oneof the plurality of carrier edge nodes.
 9. The system as recited inclaim 6 further comprising a memory including a plurality of IP trunkgroup definitions, wherein the memory is accessible by one or more ofthe core routing engine and the IP edge node.
 10. The system as recitedin claim 9 wherein the plurality of IP trunk group definitions includespolicies related to one or more of emergency call routing, IP trunkgroup directionality, and IP trunk group traffic distribution.
 11. Thesystem as recited in claim 9 wherein each of the IP trunk groupdefinitions comprises a data structure including the following fields: afirst field designating an IP trunk group identifier; a second fielddesignating an internal IP address associated with the first IP-basednetwork; a third field designating a facility name associated with thefirst IP-based network; a fourth field designating an external IPaddress associated with the first IP-based network; a fifth fielddesignating an IP address associated with the second IP-based network; asixth field designating a facility name associated with the secondIP-based network; a seventh field designating a group size; an eighthfield designating a pseudo carrier code; a ninth field designating anemergency services routing type; a tenth field designating a group routeadvance profile; an eleventh field designating a signaling normalizationprofile; a twelfth field designating a directionality indicator; athirteenth field designating a hunt sequence; a fourteenth fielddesignating regulatory nature data; a fifteenth field designating asecond IP-based network identifier; a sixteenth field designating anallowable codecs indicator; a seventeenth field designating a productidentifier; an eighteenth field designating an IP interconnection typeassociated with the IP trunk group; a nineteenth field designating aload balancer IP address; a twentieth field designating a load balancertype; and a twenty-first field designating a second IP-based networkedge node type.